The present disclosure relates to a throttling mechanism for an engine and, more particularly, to a supplementary air throttling feature for supplying air to a supplementary intake air circuit of an internal combustion engine.
To increase the efficiency of an engine, for example, when the engine is operating at low load or idle, faster combustion burn rates may be achieved by increasing turbulence in the combustion air entering the combustion chamber. By increasing the turbulence of the combustion air, better fuel-air mixing may occur.
For example, as shown in FIG. 3, an internal combustion engine 1000 includes at least one cylinder 60 with a combustion chamber 100 therein, an air inlet 120, and at least one intake port 140. A throttle body assembly 200 has a body portion 240 and a throttle plate 260, and a supplementary air assembly 400 includes a supplementary air inlet or port 420 and an air tube 440 for introducing a swirl into the combustion air to increase turbulence when engine 1000 is operating at low load or idle conditions. An idle air control valve 500 may also be provided to control throttle at supplementary air inlet 420. More particularly, in some embodiments, a flow of air travels through air tube 440 and air inlet 420 and into the intake port 140 of engine 1000. This air flow is not modulated by the throttle of engine 1000, but rather, by the separate idle air control valve 500. An engine control unit may be electrically coupled to idle air control valve 500 to control idle air control valve 500 based on predetermined parameters and/or conditions of engine 1000 during operation.